Plasma processing apparatus

Abstract

To reduce a risk of damage to a dielectric plate caused by thermal expansion of the dielectric plate, while at the same time facilitating the handling of the dielectric plate.SOLUTION: A plasma processing apparatus (1) comprises a vacuum vessel (2), an antenna (6), and a magnetic field introduction window (3). The magnetic field introduction window (3) has: a metal plate (4) which is provided with a plurality of slits (41) and has a bridging part (42); and a plurality of rectangular dielectric plates (5) covering the plurality of slits (41). The plurality of dielectric plates (5) are arranged such that adjacent sides, of the adjacent dielectric plates (5), facing each other are located on the bridging part (42).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus.

Background Art

[0002] Patent Document 1 discloses a plasma processing apparatus including a metal plate in which a slit is formed, a dielectric plate that is supported in contact with the metal plate and closes the slit, and an antenna that is provided outside the processing chamber so as to face the metal plate and generates a high-frequency magnetic field. The plasma processing apparatus disclosed in Patent Document 1 can efficiently supply the high-frequency magnetic field generated from the antenna to the processing chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the plasma processing apparatus is enlarged to increase the processing area for plasma processing, there is a problem that it becomes difficult to handle the dielectric plate when one dielectric plate is supported in contact with the metal plate as in the plasma processing apparatus disclosed in Patent Document 1.

[0005] One aspect of the present invention aims to facilitate the handling of the dielectric plate and reduce the possibility of the dielectric plate being damaged due to thermal expansion of the dielectric plate.

Means for Solving the Problems

[0006] To solve the above problems, a plasma processing apparatus according to one aspect of the present invention includes a vacuum chamber that houses an object to be processed therein, an antenna provided outside the vacuum chamber that generates a high-frequency magnetic field, and a magnetic field introduction window provided on a wall surface of the vacuum chamber for introducing the high-frequency magnetic field into the vacuum chamber to generate plasma inside the vacuum chamber. The magnetic field introduction window includes a metal plate having a plurality of slits formed therein and a bridging portion formed between the plurality of slits, and a plurality of rectangular dielectric plates arranged side by side so as to cover the plurality of slits. The plurality of dielectric plates are arranged such that adjacent sides of the adjacent dielectric plates that face each other are located on the bridging portion.

Advantages of the Invention

[0007] According to one aspect of the present invention, it is possible to facilitate the handling of the dielectric plates and reduce the possibility of the dielectric plates being damaged due to thermal expansion.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] 〔Embodiment 1〕 <Configuration of Plasma Processing Apparatus 1> FIG. 1 is a cross-sectional view showing a cross-sectional configuration of a plasma processing apparatus 1 according to Embodiment 1 of the present invention. In FIG. 1, the direction in which the antenna 6 extends is the X-axis direction, the direction from the vacuum vessel 2 toward the antenna 6 is the Z-axis direction, and the direction orthogonal to both the X-axis direction and the Z-axis direction is the Y-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. FIG. 2 is a plan view of the plasma processing apparatus 1 shown in FIG. 1. In FIG. 2, the antenna 6 and the high-frequency power supply 7 are omitted.

[0010] As shown in FIG. 1, the plasma processing apparatus 1 performs plasma processing on a workpiece W1 such as a substrate using an inductively coupled plasma P1. Here, the substrate is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic EL display, or a flexible substrate for a flexible display. Further, the workpiece W1 can be a semiconductor substrate used for various applications. Furthermore, the workpiece W1 is not limited to a substrate-like form, such as a tool, for example. The processing performed on the workpiece W1 is, for example, film formation by plasma CVD (Chemical Vapor Deposition) method or sputtering method, etching by plasma, ashing, removal of a coating film, and the like.

[0011] The plasma processing apparatus 1 includes a vacuum vessel 2, a magnetic field introduction window 3, an antenna 6, a high-frequency power supply 7, and a holding unit 8. Inside the vacuum vessel 2, a processing chamber 21 that is evacuated and into which gas is introduced is formed. The vacuum vessel 2 is, for example, a metal container. An opening 23 that penetrates in the thickness direction is formed in the wall surface 22 of the vacuum vessel 2. The vacuum vessel 2 is electrically grounded.

[0012] The gas introduced into the processing chamber 21 may be selected according to the processing content to be applied to the workpiece W1 accommodated in the processing chamber 21. For example, when forming a film on the workpiece W1 by plasma CVD method, the gas is a source gas or a gas diluted with a dilution gas such as H2. To give more specific examples, when the source gas is SiH4, an Si film can be formed, when it is SiH4 + NH3, an SiN film can be formed, when it is SiH4 + O2, an SiO2 film can be formed, and when it is SiF4 + N2, an SiN:F film (fluorinated silicon nitride film) can be formed on the workpiece W1, respectively.

[0013] <Configuration of the magnetic field introduction window 3> The magnetic field introduction window 3 has a metal plate 4 and a plurality of dielectric plates 5. The magnetic field introduction window 3 introduces the high-frequency magnetic field generated from the antenna 6 into the processing chamber 21 in order to generate plasma in the processing chamber 21. In the Z-axis direction, the metal plate 4 and the dielectric plates 5 are arranged in order.

[0014] The metal plate 4 is provided on the wall surface 22 of the vacuum vessel 2 so as to close the opening 23. A plurality of slits 41 penetrating the metal plate 4 in the Z-axis direction are formed in the metal plate 4. As shown in FIG. 2, the plurality of slits 41 extend in the Y-axis direction and are arranged in the X-axis direction. The metal plate 4 is arranged so as to be substantially parallel to the surface of the workpiece W1. Further, the metal plate 4 has a plurality of bridging portions 42. By forming a plurality of slits 41 in the metal plate 4, bridging portions 42 are formed between the plurality of slits 41.

[0015] The plurality of dielectric plates 5 are arranged side by side on the metal plate 4 so as to cover the plurality of slits 41, and the shape of each dielectric plate 5 is rectangular in plan view. The plurality of dielectric plates 5 are arranged in the X-axis direction and are not arranged in the Y-axis direction. If the plurality of dielectric plates 5 are arranged in the Y-axis direction, the boundary between the dielectric plates 5 adjacent in the Y-axis direction will be arranged on the slit 41, making it difficult to maintain the vacuum state of the processing chamber 21.

[0016] The width WD1 of one dielectric plate 5 along the X-axis direction is larger than the width WD2 of one slit 41 along the X-axis direction so that one dielectric plate 5 can cover one or more slits 41. The width WD1 of the dielectric plate 5 is, for example, 42.5 mm or more and 524.5 mm or less, and the width WD2 of the slit 41 is, for example, 5 mm or more and 30 mm or less.

[0017] Also, the width WD3 of one dielectric plate 5 along the Y-axis direction is larger than the width WD4 of one slit 41 along the Y-axis direction so that one dielectric plate 5 can cover one or more slits 41. The width WD3 of the dielectric plate 5 is, for example, 40 mm or more and 70 mm or less, and the width WD4 of the slit 41 is, for example, 30 mm or more and 60 mm or less. In this case, the widths WD3 and WD4 are determined such that the width WD3 is larger than the width WD4. The width WD1 is larger than the width WD3, and the width WD2 is smaller than the width WD4.

[0018] Furthermore, when the plasma processing apparatus 1 is viewed in the negative direction of the Z-axis, the area of one dielectric plate 5 is smaller than the area of the region where a plurality of slits 41 are formed. The dielectric plate 5 is provided in contact with the metal plate 4 from the outside of the vacuum vessel 2 and overlaps the metal plate 4. Also, the dielectric plate 5 is provided on the surface of the metal plate 4 on the antenna 6 side so as to block a plurality of slits 41 from the outside of the vacuum vessel 2.

[0019] The entire dielectric plate 5 is made of a dielectric material, and the dielectric plate 5 has a flat plate shape. The material constituting the dielectric plate 5 may be a ceramic such as alumina, silicon carbide, or silicon nitride, an inorganic material such as quartz glass or non-alkali glass, or a resin material such as a fluororesin like Teflon (registered trademark).

[0020] The high-frequency magnetic field generated from the antenna 6 passes through the dielectric plate 5 and the plurality of slits 41 and is supplied to the processing chamber 21. The vacuum state of the processing chamber 21 is maintained by the metal plate 4 closing the opening 23 and the dielectric plate 5 closing the plurality of slits 41.

[0021] <Configuration of Adjacent Dielectric Plates 5> FIG. 3 is an enlarged view of the portion surrounded by the dotted line DL shown in FIG. 2, and FIG. 4 is a cross-sectional view showing the vicinity of side 51A and the vicinity of side 52A of the dielectric plate 5A shown in FIG. 3. Reference numeral 101 in FIG. 4 indicates the vicinity of side 51A, and reference numeral 102 in FIG. 4 indicates the vicinity of side 52A.

[0022] As shown in FIGS. 2 and 3, a plurality of dielectric plates 5 are arranged on the metal plate 4 such that the adjacent sides of the adjacent dielectric plates 5 that face each other are located on the bridging portion 42. The sides of the dielectric plate 5 refer to the sides of the rectangular dielectric plate 5. As shown in FIG. 3, for example, consider the case where dielectric plates 5B, 5A, and 5C as dielectric plates 5 are arranged in this order in the X-axis direction.

[0023] The dielectric plate 5A has four sides 51A, 52A, 53A, and 54A. Among the four sides, sides 51A and 52A are a pair of short sides of the rectangle, and among the four sides, sides 53A and 54A are a pair of long sides of the rectangle. The dielectric plate 5B has a side 51B as a short side of the rectangle, and the dielectric plate 5C has a side 52C as a short side of the rectangle.

[0024] Sides 51A, 51B, 52A, and 52C extend in the Y-axis direction. Sides 53A and 54A extend in the X-axis direction. As shown by reference numeral 101 in FIGS. 3 and 4, sides 51A and 51B are located on the bridging portion 42 and are supported by the bridging portion 42. Also, side 51A and side 51B are adjacent to each other so as to face each other, and are located near the center of the width along the X-axis direction in the bridging portion 42. Side 51A and side 51B are in contact with each other.

[0025] As shown by reference numeral 102 in FIGS. 3 and 4, for adjacent dielectric plates 5A and 5C, side 52A and side 52C are adjacent to each other so as to face each other, are located on the bridging portion 42, and are supported by the bridging portion 42. A gap SP is formed between side 52A and side 52C. Not limited to the dielectric plates 5A and 5C, for each dielectric plate 5, a gap SP is formed between one short side and the short side of the adjacent dielectric plate 5, and the other short side is in contact with the short side of another adjacent dielectric plate 5 different from the said adjacent dielectric plate 5.

[0026] Thereby, even if the dielectric plate 5 expands, it is possible to prevent adjacent sides from strongly contacting each other. Therefore, no strong stress is applied to the dielectric plate 5, and the possibility of the dielectric plate 5 being damaged can be reduced.

[0027] Also, the adjacent sides of each adjacent dielectric plate 5 that are adjacent to each other so as to face each other are the short sides of the dielectric plate 5 respectively. In this case, among the four sides of the dielectric plate 5, the two sides facing each other are located on the bridging portion 42. For example, sides 52A and 52C, which are the adjacent sides of adjacent dielectric plates 5A and 5C that are adjacent to each other so as to face each other, are short sides and are located on the bridging portion 42.

[0028] Thereby, when a gap SP is formed between the short sides of adjacent dielectric plates 5A and 5C that face each other, since the gap SP is formed on the bridging portion 42, the vacuum state of the processing chamber 21 can be maintained by the dielectric plate 5. Also, as the temperature of the dielectric plate 5 rises with the generation of plasma, since the dielectric plate 5 expands thermally more in the longitudinal direction than in the short-side direction, the possibility of the dielectric plate 5 being damaged can be effectively reduced.

[0029] Furthermore, only one short-side region of the four sides of the dielectric plate 5 is fixed to the metal plate 4 on the bridging portion 42. The short-side region refers to the region near the short side on the surface of the dielectric plate 5 on the metal plate 4 side. Also, for example, only the short-side region of side 51A among the four sides of the dielectric plate 5A is fixed to the bridging portion 42 by an adhesive or a jig.

[0030] When the short-side region of side 51A is fixed to the crosslinked portion 42 by an adhesive, an adhesive is applied between the short-side region of side 51A and the crosslinked portion 42. Also, an adhesive is applied between the end face E1 of the dielectric plate 5A that contacts the dielectric plate 5B and the end face E2 of the dielectric plate 5B that contacts the dielectric plate 5A.

[0031] When the short-side region of side 51A is fixed to the crosslinked portion 42 by a jig, the jig is fixed to the metal plate 4 so that the vicinity of sides 51A and 51B is pressed against the metal plate 4 by the jig. The short-side region of side 52A is supported without being fixed to the crosslinked portion 42, and the long-side regions of sides 53A and 54A are supported without being fixed to the metal plate 4. The long-side region refers to the region near the long side on the surface of the dielectric plate 5 on the side of the metal plate 4. The short-side region of side 51B of the dielectric plate 5B is also fixed to the crosslinked portion 42 by an adhesive or a jig.

[0032] Thus, the regions of the sides of the dielectric plate 5 other than one short side are only supported without being fixed to the metal plate 4. Thereby, when the dielectric plate 5 thermally expands, the stress applied in the longitudinal direction to the dielectric plate 5 can be reduced, and the possibility of the dielectric plate 5 being damaged can be reduced.

[0033] As described above, a plurality of dielectric plates 5 are arranged on the metal plate 4, and the dielectric plates arranged on the metal plate 4 are divided into a plurality of dielectric plates 5. Therefore, compared with the case where one dielectric plate is fixed to the metal plate 4, the size of the dielectric plate 5 can be reduced. Thus, the possibility of the dielectric plate 5 peeling from the metal plate 4 due to thermal expansion of the dielectric plate 5 can be reduced, and the possibility of the dielectric plate 5 being damaged can be reduced.

[0034] Also, when the size of the plasma processing apparatus 1 is increased to enlarge the processing area of the object to be processed W1 to be plasma processed, since the magnetic field introduction window 3 is also enlarged, the area where a plurality of slits 41 are formed becomes larger. For this reason, when one dielectric plate 5 is fixed to the metal plate 4, the size of the dielectric plate 5 becomes large. On the other hand, when a plurality of dielectric plates 5 are arranged on the metal plate 4, since the size of the dielectric plate 5 becomes small, the above-described possibility can be effectively reduced.

[0035] Furthermore, the cost of the dielectric plate 5 can be reduced when using a plurality of dielectric plates 5 with a small size rather than using one dielectric plate 5 with a large size. Since the dielectric plate 5 with a small size is to be handled, it becomes easy to handle the dielectric plate 5 such as glass or ceramics which is easily damaged.

[0036] Regarding the thermal expansion of the dielectric plate 5, consider the case where the dielectric plate 5 is, for example, quartz glass. The thermal expansion coefficient of quartz glass is 0.57×10 -6 / K between 0°C and 500°C. When the length of the dielectric plate 5 in the longitudinal direction is 1000 mm and the temperature of the dielectric plate 5 rises by 500°C, the length of the dielectric plate 5 in the longitudinal direction extends by 0.285 mm.

[0037] Note that it is not preferable that one of the adjacent dielectric plates 5 is fixed and the other dielectric plate 5 is supported without being fixed on one cross-bridging portion 42. This is because when a plurality of dielectric plates 5 are arranged on the metal plate 4, there is a possibility that a problem may occur due to the displacement of the dielectric plates 5. For this reason, as shown in FIG. 2, on one cross-bridging portion 42, it is preferable that the adjacent dielectric plates 5 are both fixed, and on another cross-bridging portion 42, the adjacent dielectric plates 5 are both supported without being fixed. Thereby, the structural reliability of the dielectric plate 5 is improved.

[0038] Antenna 6 is linear and is provided outside the vacuum chamber 2 and is arranged to face the magnetic field introduction window 3. The length of the antenna 6 along the X-axis direction is approximately 2000 mm. The antenna 6 is arranged to be substantially parallel to the surface of the workpiece W1. When high-frequency power is applied to the antenna 6 from the high-frequency power supply 7, a high-frequency magnetic field is generated. As a result, an induced electric field is generated in the space within the processing chamber 21, and an inductively coupled plasma P1 is generated in that space. The holding unit 8 is a stage that is accommodated within the processing chamber 21 and holds the workpiece W1.

[0039] The high-frequency magnetic field generated from the antenna 6 passes through the plurality of dielectric plates 5 and the plurality of slits 41 and is supplied to the processing chamber 21. The vacuum state of the processing chamber 21 is maintained by the metal plate 4 that closes the opening 23 and the plurality of dielectric plates 5 that close the plurality of slits 41.

[0040] 〔Embodiment 2〕 Embodiment 2 of the present invention will be described below. For the sake of convenience of explanation, members having the same functions as those described in Embodiment 1 are given the same reference numerals, and the description thereof will not be repeated. FIG. 5 is a diagram showing the configuration of the plasma processing apparatus 1A according to Embodiment 2 of the present invention. In FIG. 5, the antenna 6 and the high-frequency power supply 7 are omitted. As shown in FIG. 5, the plasma processing apparatus 1A is different from the plasma processing apparatus 1 according to Embodiment 1 in that a buffer material 9 is provided.

[0041] A buffer material 9 is provided between the adjacent sides of the respective adjacent dielectric plates 5 that are respectively fixed to the metal plate 4 on a specific bridging portion 42 so as to face each other. For example, for adjacent dielectric plates 5A and 5B, a buffer material 9 is provided between side 51A and side 51B. The buffer material 9 is, for example, a resin material such as Teflon (registered trademark).

[0042] By providing the buffer material 9 between the sides fixed to the metal plate 4 on the bridging portion 42, even if the dielectric plate 5 expands in the longitudinal direction, it is possible to prevent the adjacent sides from strongly contacting each other. Therefore, no strong stress is applied to the dielectric plate 5, and the possibility of the dielectric plate 5 being damaged can be reduced.

[0043] 〔Summary〕 The plasma processing apparatus according to Aspect 1 of the present invention includes a vacuum chamber that houses an object to be processed therein, an antenna provided outside the vacuum chamber that generates a high-frequency magnetic field, and a magnetic field introduction window provided on the wall surface of the vacuum chamber for introducing the high-frequency magnetic field into the vacuum chamber in order to generate plasma inside the vacuum chamber. The magnetic field introduction window has a metal plate formed with a plurality of slits and having a bridging portion formed between the plurality of slits, and a plurality of rectangular dielectric plates arranged side by side so as to cover the plurality of slits. The plurality of dielectric plates are arranged such that adjacent sides of the adjacent dielectric plates facing each other are located on the bridging portion.

[0044] The plasma processing apparatus according to Aspect 2 of the present invention may be configured such that, in the above Aspect 1, a gap is formed between the adjacent sides facing each other.

[0045] The plasma processing apparatus according to Aspect 3 of the present invention may be configured such that, in the above Aspect 1 or 2, the adjacent sides facing each other are each a short side of the dielectric plate.

[0046] The plasma processing apparatus according to Aspect 4 of the present invention may be configured such that, in the above Aspect 3, only one short side region of the four sides of the dielectric plate is fixed to the metal plate on the bridging portion.

[0047] The plasma processing apparatus according to Aspect 5 of the present invention may be configured such that, in the above Aspect 4, a buffer material is provided between the adjacent sides of the adjacent dielectric plates fixed to the metal plate on a specific bridging portion and facing each other.

[0048] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Description of Reference Numerals

[0049] 1, 1A Plasma processing apparatus 2 Vacuum chamber 3 Magnetic field introduction window 4 Metal plate 5, 5A, 5B, 5C Dielectric plate 6 Antenna 9 Buffer material 22 Wall surface 41 Slit 42 Bridging portion P1 Plasma SP Gap W1 Object to be processed

Claims

1. A vacuum chamber for accommodating an object to be processed therein, An antenna provided outside the vacuum chamber for generating a high-frequency magnetic field, A magnetic field introduction window provided on a wall surface of the vacuum chamber for introducing the high-frequency magnetic field into the vacuum chamber to generate plasma inside the vacuum chamber, and The magnetic field introduction window A metal plate having a plurality of slits formed therein and a bridging portion formed between the plurality of slits, A plurality of rectangular dielectric plates arranged side by side so as to cover the plurality of slits, and The plurality of dielectric plates are arranged such that adjacent sides of the adjacent dielectric plates facing each other are located on the bridging portion, The adjacent sides facing each other are each a short side of the dielectric plate, The dielectric plate is fixed to the metal plate on the bridging portion only in a short side region of one of the four sides of the dielectric plate, and a plasma processing apparatus characterized by this.

2. The plasma processing apparatus according to claim 1, wherein a gap is formed between the adjacent sides facing each other.

3. The plasma processing apparatus according to claim 1 or 2, wherein a buffer material is provided between the adjacent sides of the adjacent dielectric plates fixed to the metal plate on a specific bridging portion and facing each other.

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